Update README

Author: matthewmcneely

README.md

@@ -596,6 +596,8 @@ To build and install pydgraph locally, run
 pip install -e ".[dev]"
 ```
 
+#### Regenerating protobufs
+
 If you have made changes to the `pydgraph/proto/api.proto` file, you need need to regenerate the
 source files generated by Protocol Buffer tools. To do that, install the
 [grpcio-tools][grpcio-tools] library and then run the following command:
@@ -612,9 +614,13 @@ users with older grpcio versions, providing a graceful upgrade path. It also use
 eliminates Python 3.12+ deprecation warnings. The dev dependencies in `pyproject.toml` are pinned to
 the correct version (grpcio-tools 1.65.x)
 
+If you are using python version 3.13 or higher, an error will be raised if you try to run
+`scripts/protogen.py`. This is to prevent generating protobufs that are incompatible with older
+grpcio-tools versions.
+
 #### grpcio 1.65.0 is the minimum version
 
-While we would prefer to support older grpcio versions, practical limitations prevent this:
+Older grpcio versions have practical limitations:
 
 - **Compilation failures**: grpcio versions older than ~1.60.0 fail to compile from source on modern
   systems (macOS with recent Xcode, newer Linux distributions) due to C++ compiler compatibility